Fig. 3
Allele-specific inhibition of IgA-induced ROS production by SIRL-1. a Comparison of the SIRL-1 expression on monocytes expressing FcγRIII-, FcεRIa- or FcαR-receptors. Flow cytometry analysis of the SIRL-1 surface expression is shown for monocytes gated on the expressing of the Fc-receptors FcγRIII, FcεRI or FcαR (gating strategy is shown in Additional file 5). The SIRL-1 specific staining (black lines) is shown in reference to the isotype control (gray). b Allele-dependent inhibition of ROS production. FcαR-mediated ROS production is shown for primary monocytes induced by plate-bound IgA in the presence of agonistic anti-SIRL-1 antibodies (filled circle) or isotype-matched control antibody (open circle). Representative examples are shown for each of the three rs612529-genotypes. ROS production was measured by ELISA at λEx/λEm = 545/590 nm using H2O2 sensitive Amplex Red; the units represent background corrected relative fluorescence unit (RFU). c ROS inhibition obtained for a cohort of 30 genotyped donors. The plots display the SIRL-1 surface expression (left panel) and the percent inhibition of the IgA-induced ROS production (right panel) in reference to the respective rs612529 genotype. d The correlation of SIRL-1 expression with the inhibition of IgA-induced ROS production. The correlation shown is 30 individuals. Dashed line represents the linear regression. rs612529 genotype is indicated by the color code (TT: blue, CT: gray; CC: red)